The purposes of this study are to determine the response rate and duration of response to topotecan administered as a continuous infusion for 72 hrs. every 7 days in patients with platinum resistant ovarian cancer. Further objectives are to (1) describe the toxicity associated with this regimen; (2) determine topotecan pharmacokinetic parameters; (3) determine the topoisomerase-1 activity of visceral metastases and describe if enzyme levels correlate with clinical response to topotecan.